1. Field of the Invention
The present invention relates to a method for solidifying soil and industrial waste and a solidified material obtained thereby. More particularly, the present invention relates to a method for solidifying soil and industrial waste, in which a solidified material of soil and industrial waste, having physical properties that enable it to be used as a substitute for stone material, can be prepared by adding a solidifying agent, containing straight asphalt as a main component, and a small amount of cement, to a single kind of soil or a mixture of soil, such as decomposed granite soil, mud, river sand and sea sand, and a single kind of industrial waste or a mixture of industrial waste, such as slag, powder slag, waste concrete and sludge, as well as a solidified material prepared by said method.
2. Description of the Prior Art
These days, due to the difficulty in securing good-quality construction materials in the public works and construction industries, the construction period is lengthened, thus increasing expenses. Also, to secure construction materials, stony mountains are exploited or aggregate is extracted from rivers, sea floors and the like, thus destroying the natural environment and disturbing ecosystems. Specifically, because granular materials such as stone materials are used in harbor reclamation and asphalt and concrete paving, fields and mountains are destroyed to quarry stones, and stone cutting, transport and breaking work act as factors increasing construction expenses. In addition, because general soil is used in most riverbank construction, dikes break due to the reduced durability and safety caused by scouring resulting from water stream pressure, thus causing flood damage and the spread of disease. Also, in the case of soft ground improvement according to the prior art, a high construction cost is incurred, and the loss of material used is high.
To solve these problems, there have been attempts to recycle soil and industrial waste, widely distributed throughout Korea, as a substitute for stone materials in various public works and other construction industries.
In such attempts, cement stabilization methods, LAC (lignin rosin asphalt concrete) methods and the like have been developed and used. However, the materials corresponding to these methods show a long curing time, making it difficult to obtain early compressive strength, and also have a low compressive strength of 100 kgf/cm2. For this reason, the application of these materials has been limited to sub-base layer materials in road construction and the like.
In another attempt, Korean Patent Laid-Open Publication No. 1996-29280 discloses a method of curing a mixture of industrial waste and soil using a curing agent composition. In this method, the curing agent composition comprises 25% sodium carbonate, 25% potassium chloride, 15% magnesium carbonate, 10% ammonium chloride, 8% potassium silicate, 7% silicate, 5% ferrous sulfate and 5% titanium oxide. The curing agent is described as being suitable for solidifying a mixture of industrial waste and soil, but it contains sodium carbonate and potassium chloride as main components, and thus it is expensive. Also, the strength of the solidified materials prepared using the curing agent is not greatly increased, and thus there is a need to develop a solidifying agent which can further increase the strength of the solidified materials.
As described above, stone materials can be used in a wide range of applications, including harbors, foreshores, roads, airports, water resources development, soil and public works, but the resources thereof are restricted. For this reason, there has been an urgent demand for a method of enabling the recycling of industrial waste, which are generated in construction fields in large amounts and are readily available, and soil such as decomposed granite soil.
According to this demand, the present inventors filed a patent application relating to a solidifying composition containing 25-35 wt % of emulsified asphalt, 0.05-0.20 wt % of an emulsifier for asphalt, 0.1-0.3 wt % of hydrochloric acid, 0.01-0.05 wt % of calcium chloride, 0.1-0.5 wt % of lignin, 0.01-0.05 wt % of oleic acid, 0.005-0.030 wt % of a surfactant, and the balance of water (Korean Patent Application No. 2005-0070706, filed on Aug. 2, 2005). However, this composition has problems in that it contains emulsified asphalt, which increases the production cost of the composition, and it shows insufficient impact resistance and low flexibility.